There are certain microbiological systems known for measuring toxicity. They all involve one single microorganism. Some of them are given in table 1 below.
TABLE 1Various microbiological systems used for measuring toxicityAssay nameOrganism/CompoundTypeMicroplate assayCryoalgotoxSelenastrum capricornutumalgaexalgaemembrane filterE. colibacteriaMicrotoxPhotobacterium phosphoreumbacteriaxMetPLATExERODetoxy-resorufin-O-deethylaseenzymexECHAdehydrogenaseenzymeMetPADenzymesPs.fluorescencebacteriaSOSMAxSOS-chromotestE. colibacteriaxSOS lux testE. colibacteriaAmes testS. typhimuriumbacteriamicronucleusPleurodeksamphibianCaenorhabditis elegansnematodeSpirotoxSpirostomum ambiguumprotozooxDaphnia magnacrustaceaToxi-ChromotestE. colibacteriaArtemia salinacrustaceaxCALUXEnzymePolytoxbacteriaVITOTOXSalmonella typhimuriumbacteriaMETIERChironomus ripariusTOXKITdormant larvaeAquatic invertebrate
However these above systems have drawbacks, such as that some has a need for a long sample preparation time and have a high price. Further they may not be read visually which applies for Microtox above. Thus there is in certain of the above systems a need for high cost reading equipment. Time for training of staff would also be considerably longer for some of the systems above.
Biochemical fingerprinting of bacteria is a technique that is used for typing bacterial strains, either to the species level, or for typing below the species level. The unknown bacteria are cultivated in the presence of several different standard chemical compounds, and the ability of the bacteria to metabolise the compounds is measured (the biochemical fingerprint). The results are obtained as a set of quantitative data, and identification of the bacterial strain can be performed by comparing the data to biochemical fingerprints stored in a database that has previously been made using known bacteria. The identification of a bacterial strain to the species level will provide valuable information on the bacteria regarding e.g. pathogenic properties. This method however may not be used for determining toxic effects of unknown chemical compounds.